Power actuator



C. S. BRAGG ET AL POWER AGTUATOR Oct. 8, 1929.

Filed March 13. 1926 2 Sheets-Sheet l ATTORNEY Oct. 8, 1929. c. s. BRAGG Er AL POWER ACTUATOR Filed March 15. 1926 2 Sheets-Sheet 2 INVENTOR 5 the return movement of t hereinafter described, reference bein Patented Oct. 8,l 1929 UNITED STATES PATENT OFFICE CALEB SMITH BRAGG, 0F PALM BEACH, FLORIDA,- AND VICTOR W. KLIESRATH, 0F PORT WASHINGTON, NEW YORK, ASSIGNORS'TO BRAGG-KLIESRATH CORPORATION, 0F LONG ISLAND CITY, NEW YORK, A CORPORATION 0F NEW YORK POWER ACTU'ATOR Application led March 13, 1926. Serial No. 94,412..

` Our invention consists in the novel features 0 had/gto the accompanying drawings which illustrate several embodiments of the same, selected by us for purposes of illustration, and the said invention isv fully disclosed in the following description and claims.

The object of our invention is .to provide a Yery simple form of power actuator for actuating the brake mechanism. of automotive vehicles having a cylinder and single acting piston thereinconnected with the brake mechanism, lthe said Apiston being normally subjected either to atmospheric pressure on opposite sides, or to suction or'partial vacuum on opposite sides, and provided with controlling valve mechanism operated by an operator operated part, preferably the ordinary foot lever or. pedal lever, the valve mechanism being preferably located in linkage connecting the operator operated part with the q brake mechanism and connected with the cylinder by flexible piping, the connections b'etween the loperator operated part and the valve mechanism being such that a relative movement is permitted between the Valve actuating means and the valve casing 'sufficient to insure theoperation of the valve, and after this lost motion is taken up, the operator may exertl his physical force on the brake mechanisnl, either in addition to the force of the actuator, or on failure of power.. 'We also prefer to provide a certain amount of lost motion in the connections between the actuator piston and the brake mechanism, so that in case of failure of power, the brake mechanism may be actuated by the physical force of the operator applied to the pedal, lever, without moving the piston at all. The power stroke of the actuator is secured by atmospheric pressure-on one face of the piston actingvagainst suction or rarification on the other face under the control of the valve mechanism, the suction being conveniently obtained from the suction passage ofthe internal combustion engine employed to rpropxel the vehicle, and

v e pistonis obtained by equalizing ythe pressures on opposite faces of the piston, andpermitting the brake mechanism, by its own draft or load, to retract the piston so as to free the friction 'surfaces of the brake mechanism, and by means of the usual retracting spring, restore the brake also in connection with an actuator in which the piston is normally submerged in air at atmospheric pressure.

Our invention also includes certain` novel constructions and combinations of parts hereinafter described and pointed` out in the claims.

In the accompanying drawings,

Fig. 1 is a diagrammatic view showing an installation in an automotive vehicle embodying our present invention, in which the piston is normally submerged in vacuum.

Fig. 2 is an enlarged View of the actuator cylinder and piston, and the valve mechanism therefor, illustrated in Fig. 1.

Fig. 3 is a detail viewillustrating a slight- 'ly different manner of connecting the piston of the actuator with the brake mechanism, so as to permit the operation lof the brake mechanism bythe foot lever in case of failure of power, without moving tlie piston. y

F ig.. l is a view similar to Fig. 1,'illustrating our present invention inconnection with an actuator in which the piston is'normally submerged in air at atmospheric pressure.

Fig. 5 is an enlarged view similar to Fig.

2, showing the actuator cylinder and piston,

and the valve mechanism therefor, illustrated in Fig. 4.

Referring tothe-embodiment of our invention illustrated" inFigs. land 2, l, represents the actuator cylinder, which in this instance at both ends, as by heads, 2,2, In this instance the head, 2, is shown integral with the cylinder and/the head, 2, bolted or otherwise secured thereto. For convenience of installation, the end ofthe cylinder adjacent to the head, 2, may be provided/with a projecting ange, indicated at la, having bolt holes for attaching the head, 2a, to the cylinder, and the/cylinder to the chassis, and the cylinder adjacent tothe head,'2, is shown-provided with lateral proj ecting portions, indicated at 1b, which may he in the form of an annular flange, if preferred, either formed integrally with the head, 2, or riveted or otherwise secured thereto and provided with bolt holes for attaching it to thechassis. The cylinder may be conveniently formed as a stamping, or it maybe formed of Cast metal and with separate heads attached in any usual or preferred manner. 3 represents a single acting piston located von the cylinder and provided with a gasket, 4.- The piston is provided with a hub, in this instancd formed in two parts, 7

-and 7 a, one part being formed separately dand cordingto the manner in which it is installed.

The piston rod, 5, is conveniently provided with a shoulder, indicated at 8, which may be v on the collar to which the lug, 9, is attached for engaging the outer end of the head, and limiting the rearward movement of the piston. In

vthis instance we have shown in the diagram,

Fig. 1, the piston rod, 5, connected by a link, 73, with 'an arm, 74, on a rock shaft, 75, pro'- vided with arms, 76, and, 32,` the arm, 32, connected by link, 31, with the valve sleeve,

' 20, of the valve mechanism, 10, .and arms, 76,

connected by links, 77, within this instance, brake mechanism for two wheels of thevehicle, for example, the two rear wheels. 1t is to be understood that our invention is applicable to any type ofbrake mechanism, and that it may be applied by any intermediate connections, whether mechanical or hydraulic, to brake mechanism for one or more lwheels of the vehicle or trailer, as may be found desirable. In the present instance, each of the brake mechanisms illustrated in the diagram, Fig. 1, include a friction drum, 70, brake band, 71, a brake lever, 72, and a suitable retracting spring therefor, indicated at 72a.

vIn this instance, the valve mechanism is lonism be'ingconnected -with the cylinder and with the source ofk suction by a flexible piping to -permit the valve mechanism to move longitudinally. lheJ-'alve mechanism comprises a `.valve 'casing and a'pair of valves'capable of movement longitudinally of the casing,

Asaid valve casing and valves being, the one connected with the operator operated part,'or foot lever, 88, and the other with the brake mechanism. 1n the present instance the valve casing is shown connected with the foot leverv and the valves are carried by a valve operating part, or sleeve,connected with the brake mechanism, as hereinafter. described. The valve casing, indicated at 10, is conveniently formed in two parts, bolted together, and provided interior-ly with a centrally located valve chamber, 17, provided with oppositely disposed valve seats, 15 and 16, surrounding yapertures communicating respectively with chambers 13 and 14. The valve casing is also provided.,- for convenience, with threaded apertures, -11' and 12, communieating respectively with the end chambers, 131and 14, on opposite -sides of the valve chamber, to either ofI which the pipe connection to the actuator `cylinder may be attached, as desired, the other aperture being open tothe atmosphere, or connected to the other source of higher pressure fluid. The end of the valve casing, adjacent to the foot lever,- 88, is in this instance shown closed and provided with a threaded aperture to' receive an adjustable, threaded link/rod, 25, provided with a set nut, 25h, for reasons'which will be explained late r, the forward end of the link rod, 25, beingpivotally connected to the foot lever, 88. rlhe opposite end of the valve casingis provided with a stuffing box to accommodate a'longitudinally movable valve actuating sleeve, 20, extending therethrough, and engaging a guiding recess, 10a, at the opposite end of the casing. Forl reasons which are hereinafter explained, the rear end of the valvecasing is shown .provided with an interiorly threaded aperture, 10b, to receive an adjustably threaded sleeve, 21, provided with a set nut, 22, and having an enlarged head portion, 23, in which the stuffing box, indicated at 24, for the sleeve, 20, is located. The sleeve, 20, isclosed-at its inner ,end, as by a plug, 26, and is provided with a plurality of apertures, 27, for establishing communication at all times betweenthe interior of the sleeve, 20, and the valve chamber, 17, of the valve casing. f

Upon the valve sleeve and within the chamber, 17 are located a pair of oppositely disposed valves, 40, 41, for engaging the valve seats, 15,16, respectively, the said valves being movable with respect to the sleeve. v These valves are preferably'made of molded rubber, although this is not essential, and each valve is provided with a central aperture fitting the sleeve, 20, so 'tightly as to prevent leakage between the valve and sleeve, while permitting the movement of. the sleeve therethrough. Each of the said valves when made of molded rubber, may be provided with conical recesses, for assisting in making a tightkjoint between the valves and the sleeve, as shown in our former application for Letters and 41, are lnormally pressed in opposite diy rections against the seats, l5 and 1 6, respectively, by yielding means, as springs, -.50,' and the sleeve, 20, is provided with collars, 40il and 41a, for engaging the exterior faces of the respective valves, 40 and 41, for the purpose of moving one jor the other in a di-` rection to open/the valve. The collars, 4()a and 41a, are soY located with respect to the valves, as indicatedin Figi/2, that when the parts are in normal position, as indicated in that figure, the collar., 40a, isreleased, theA valve, 40, permitting it to seat, and the collar,

41a, is in engagement with the valve, 41, and holds it slightly off of its seat, thereby establishing communication between the rear end chamber, 14, the valve chamber, 17, and the interior of the sleeve, 20. y.

' Yielding retracting mea-ns are provided for returning thefoot pedal andvalve mechanism to, and holding them in ythe normal position, asi indicated in Figs. 1 and 2. In this instance the lever pedal, 88, is shown as provided with a retracting spring, 89, normally tending to pull the leyer and valve casing rearwardly, or in a direction opposite to the arrow, until the collar, 8, on the piston rod, 5, engages ythe outer eiid of the piston head, 2, and the construction is such :that when the foot lever is in its normal position, the valve casing will be in its rearward position with respect to the sleeve20, the fotiward end of the sleeve being in engagement with a shoulder, 10", or the end of the adjustable link rod, 25, at the forward endof the recess,

10, in the valve casing, which limits the relative movement of the valve casing and sleeve, 20, in one direction. The relative movement between the valvesing and sleeve in the opposite direction is limited adjustably by means of a stop collar, 28, on the sleeve, 20, within the chamber, 14, of the valve casing, which collar, 28, is adapted to engage the inner end of the adjusting sleeve, 21, and

thereby limit the extent of opening of the valve, 40, when the valve casing is moved foriward in the direction of the arrow, in Fig. 2. It will thus be seen that there is a'limited amount of lost motion provided between the valve casing, 10, and the valve actuating sleeve, 20, the extentl of which is adjustable by' means of the sleeve,'21, and the link rod, 25. It will also be seen that whenever this lost motion is taken up by moving the valve casing in the direction of the arrow in Fig. 2, far enough to bring the stop collar, 28, into contact with the adjustable sleeve, 21, the furtherforwardy movement of the foot lever will enable the operator to apply his physical `actuator in rear of mechanism and the sleeve, 20, hereinafter described, in addition to the force exerted by the actuator, or for the operation ofthe brake mechanism directly by the physical force of the operator in case of failure of ptver. By adjusting the sleeve, 21, and the link ngd, 25,

4and securing them in adjusted position by the set nuts, 22 and 25h, the extent of opening of the valves, 40 and l41, can be regulated. The valve sleeve is provided withmeans for connecting it with the brake mechanism in this instance, and also with means for connecting Vit with a flexible pipe connection. In this instance the valve sleeve is shown as provided with a cap, 29, screw threaded, or otherwisesecured thereto, and lhavingra perforated lug, 30, which is connected by a link rod, 31, with an arm, 32, on the rock shaft, 75, thereby connecting the valve actuating sleeve positively with the brake mechanism. The cap, 29,-is also provided with a pipe connection, indicated at 32, to which a flexible pipe, `or tube', may be connected.- p

The same form of valve mechanism can be used with an actuator in which the piston is normally submerged in vacuum, and with an actuator in which the piston is normally suhmerged in atmospheric air, and in either case, the same valve 41, which we term the equaliz- `ing valve, is normally held open when the opthe closing of the equalizing valve creates l 'differential pressures on opposite faces of the piston.

In the installation indicated in Figs. 1 andl 2, in which the piston is normally submerged in vacuum, 41, is the equalizing valve, and 40 is the differential valve. A vacuum pipe, indicated at 62, extends from the intake mam? fold, 61, of the internal combustion engine, indicated at 60, preferably at a point between the throttle valve, 64, and carburetor, 63, and the engine cylinders, as shown, and this pipe, 62,"is connected to the cylinder, 1, forward of the piston, as indicated in Figs. 1 and 2. The cylinder, forward of the piston, is also connected by a flexible pipe section, indicated at 62, with 'the chamber, 14, of the valve casing, as by means of a fitting, 62h, the pipe 62, being preferably connected, as shown, directly to the cylinder at a different point fron'n the pipe 62, but on the same side of the piston; The suction pipe, 62, is preferably provided with a check valve, indicated at 65, and 4a restricting valve, indicated at 67. The pipe connection 32, for the valve actuating sleeve, 20, is also connected by means of a flexible pipe 66, with the cylinder, 1, of the the piston, as shown in F igs.- 1 and 2. f;

The parts being in the position indicated in Fig. 2, the piston being in its fully retracted position, which determines the noras disclosed in Aourformer applicationv forv Letters llfatent, filedDecember 22, 1923, Sef, f-y rial No. 682,346, although the extent to which valve, 41, may be opened, can be limiti-id by'f operation of the brake mechanism effects the mal or off position ofthe brakes, of the'valveJ actuating sleeve, of the valve casing, and of the pedal lever, and assuming that the engine I is running so that the suction of the intake vmanifold is available whenever the throttle is closed, or partially closed, the section of the manifold will .withdraw through thesuc- `the valve chamber, ,17the valve-,l fend chamber, 14, in the valve casing, and the pipe, 62a. -We prefer to provide a. means for regulating the quantities of air which' zmay' be withdrawn from the cylinder into j the lintake manifold, and in thisinstance,providean adv `,pres si`1re on the pedal everv sufficiently to justable restrictingvalve, 6 7, in the pipe, 62',

the adjustable sleeve, 25, as will be explained in our description of Figs. Il and 5.V As soon as the air in the cylinder on both sides of the pistbjn. is exhausted, no further air will bemwithdrawn and delivered into the vintake manifold, until after an actuation ofthe brake mechanism, while the actuator is `in condition to secure an immediate power stroke, by simply admitting air as rapidly as desired under atmospheric pressure to the cylinder in rear of the piston. To applyl the brakes, the operator will press the foot lever, 88, forward in the usual manner, thereby eecting a` relative movement of the valve casing with respect to the valve actuating sleeve, 20, and valves,.in the direction of the arrow in Fig. 2.

This permits the valve, 41, to close, Or seat,

thereby disconnecting the cylinder in rear of the piston from the suction pipe, 62, after which the valve, 40, is opened, 'admitting air aty atmospheric pressure through the aperture, 11, in the valve casing, into the valve chamber, 17, and through the apertures, 27, the valve actuating.' sleeve, 20, and pipe, 66, to the cylinder in rear ofthe piston, effecting an immediate forward movement of the piston under full power, without, however, admitting any appreciable quantities of air-to the intake manifold. As the piston moves forward, in the direction of the arrow in Fig. 2, lthe brake mechanism is applied, and the forward movement of the ValVesleeVe, 20, andvalves independent of the valve casing within the limits of the lost motion, through the arm, 32, of the rock shaft, 75, and the link rod, 31, so that the forward movement of the. piston continues so long as the foot lever, 88, is moved forward, and enables the operator to apply the brakes to the desired eX ent. As soon as the forward movement of the foot lever stops, the continued forward movement of the piston will cause a continued forward movement of the valve sleeve, 20, and the valves, and effect a relative movement between the said sleeve'and valves and thevalve casing, sufficient to close the valve,-{l0, and shutoff the supply of the higher pressure iuid, to w/it, atmospheric air, and permit the piston to hold the brakes as lapplied. The slightest subsequent movement of the piston eithervdirection would ,either open suc-tion valve, 41, vor atmospheric valve, 40', to-elther increase or decrease the 'state of raril'ication within the cylinder to the rear ofthe piston, and so automaticallyl maintain a balanced condition between the pressure exerted on the piston andthe draft lease the brakes, the o erator-releases the' permit the spring, 89, .to retract the pedal ylever and valve casingfwith respect to the valve sleeve,and effect the opening of the -valve, 41;, which will by-pass air from the Yrear to the front of the pistonand reduce the differential of pressures on opposite sides of the piston, an allow the draft of the applied brakes to retract the piston sufficiently .to release the engaged frictionalsurfaces of --the brake mechanism to the desired extent.

rlhe brakes can be re-applied by a forward movement ofthe pedal lever, suliicient to close the valve, 41, and open the valve, 4.0.

When the operator removes his foot from the foot lever and releases it, the spring, '89, will cause the rearward movement of the valve casing, l0, with respect to the valve actuating sleeve, 20, toagain open the valve, 41, and connect the cylinder in rear 0f the piston and the cylinder forward of the piston through the pipe, 62, thereby equalizing the pressures on opposite sides of the piston, so as to per-` `mechanism, pressures are equalized on opposite sides of the piston to permit the brakes Aof the brakes as applied. To partially reto immediately release themselves, after which .the air previously admitted to effect the operation of' the brake mechanism is withdrawn from the cylinder on both sides of the piston, into the intake manifold, the restrictirrg valve in the suction line, 62, serving to prevent the delivery of air into the intake manifold insuch quantities as to stall the engine, if idling. 'By connecting the pipe, 62a, directly to the actuator cylinder forward of the piston, and connecting the suction pipe, 62, .to the same portion of the cylinder, but at a diderent point, it will be readily seen Fig. 3.

that the end portion of the cylinder forwardof the piston forms a vacuum storage, space, so that when the valve, 41, is opened after actuation of the brake mechanism, a large proportion of the air previously admitted in rear of the cylinder, is instantly transferred to this storage space forward ofthe piston, and the pressures within the cylinder on opposite faces of the piston will instantly be# come equalized so as to permit an instant release of the brakes, and the suction through pipe, 62, will thereafter withdraw the air previously admitted toiactuate the brake mecha'- Iiism, equally from both sides of the piston under the control of the restricting valve, or other restricting means of 'less area than the pipes, 62 and66, and the valve mechanism.

It will be understood that when theoperator hasK moved the lever, 88, forward, so as to apply the brake mechanism, he may, by exerting further pressure on the foot lever, move the rod, 20, far enough forward to bring the sleeve, 21, into engagenientwiththe colla-r, 28, on the sleeve, 21, so as to transmit the physical force of the operator to the brake mechanism in addition to the power exerted by the actuator piston. It will also be seen that in like manner, upon failure of power` the operatoi' can apply the brakes by physical force alone, by depressing thefoot lever, 88, so as to bring the sleeve, 21, into engagement with the collar, 28. In so doing, the taking up of the lost motion provided betweenthe valve actuatng sleeve and'valve casing, will place the valve in such position as to vent the cylinder so that the piston can be moved without any more resistance than the frictional resistance between the piston and cylinder, where the link rod, 7 3, from the piston, is connected to the arm, 74, without provision for lost motion. We, however, prefer to provide lost motionA between these partsA or in connection therewith, for which purpose we conveniently employ the construction illustrated in In thisfigure, the connecting rod, 73, is provided at its rear end with a `horizontal slit, 7 3, ladapted to engage a pin, 74, carried by the ariir, 74. yThis lost motion may,

` however, be provided in other ways. Where such lost motion in-provided, it will be seen v that in case of failure of power, the operator can, by means of .the foot lever, 8,8, operate the`l brake mechanism directly through the connecting rod,-22, and arms, 78, without moving the piston. In this case, the resulting movement of the rock shaft,- 7 5, and arm, 74,

` in Ithe application of the brakes, merely portion of it to causes the pin, 74, onthe arm, .74, to travel ,along-the slct,\73, wit-hout imparting motion to the piston. ,This construct-ion enables the operator to applyA his entire force to the applicationof lthe brakes without diverting any eii'ect the movement of the `piston.

In Figs.4 and 5, we have shown an embodiment of our present invention in which't-he actuator pistonv is normally submerged in air at atmospheric pressure, that is to say, the cylinder is normally in communication with the atmosphere on both sides of the piston, 1

and the powerstroke of the actuator is effected by withdrawing the air from the cylinder forward ofthe piston. In these figures, the actuator cylinder, indicated at 101, is provided with a. closed head, 102, at

one end, and at the other end is open to the atmosphere. The construction of the cylinder and piston is otherwise identical with the construction of the cylinder and piston previously described, and the various parts have been given the same reference characters with the addition of 100, and need not be again described. Y

Likewise, the valve mechanism shown in 'detail in Fig. 5, is constructed exactly as premechanism, and the connection between it and the actuator piston, and the connections between the foot lever and valve casing,vand

between the valve actuator rodand the brake mechanism 4"and actuator piston. The mai/n difference between the two forms or'einbodiments of our invention, is in thepipe connections between the'valve mechanism and suction pipe'leadingto the'manifold, and between the valveinechanism and the cylinder, which will be specifically described. In this instance the suction pipe, 162, is connected to thelaperture, 11, at Ithe forward end of the valve casing, and.the aperture, 112, is open to the atmosphere, while the connection132, communicating with the interior of the valve actuating sleeve, is connected by a pipe, 166, with the actuator cylinder, 101, forward of the piston.. In this installation, the valve, 141, is the equalizing yalve, and is normally held open to connect the aperture, 112,`with the cylinder forward of the piston, whilev the valve, 140, is thel differential valve, and in this instance eHects, by its opening, the communication between the suction pipe and the cylinder forward of the piston, the op osite face of the piston being at all times subjected to atmospheric pressure. v The parts being in normal position, as indicated in Fig. 2, it will be seen that atmospheric air has free access to the cylinder forward of the piston, through the aperture, 112, of the valve casing, 110, the end chamber, 114, through the partially opened valve, 141, and

through the valve sleeve, 120, and pipe, 166,/

while the rear face of the piston is also acted on by the atmosphere, so that the piston, 103, may be properly said to be submerged in air at atmospheric pressure. Communication between the suction pipe, 162, and the actuator is cut off by the Valve, 140, which isnormally closed, -and nb, air can pass to the intake mani fold of the engine. To effect an application'- `of the brakes in vthis construction, thel foot* lever, 188, is depressed, thereby moving the valve casing, 110, in the direct-ion of the arrow, Fig. 5, with yrespect tothe valve actuating sleeve, 120, thereby' closing the valve, 141, shutting olf communication between the atmosphere and the cylinder forward` of the piston, and opening the-valve, 140, thereby placing the suctiony pipe in communication with the valve chamber, 117, the interior of the sleeve, 120, exible pipe, 166, and thecyl inder of thevactuatorv forward ofthe piston. As no restricting valve isused in the suction line, 162, we provide means for-regulating the opening `of the valve, 140,whicl1k in this y instance is'the suction valve, to prevent' the withdrawal of air in such large'quantities at a time as to stall the engine, if idling.' The sleeve, .121, may be adjusted a`n`d vsecured in such relation to the collar, 128,so that a variably restricted or limited opening-'of the valve, 140, is permitted, which acts'as a. r'estricting device to regulate the delivery of lthe air to th'emanifold. y Obviously, as soon as the valve,'140, is opened, and the atmospheric press-ure, forward of the piston, is reduced and raried, the pressure of atmospheric air on the rear face of the piston will lmove the piston and valve sleeve, 120, forward, in the direction of the arrows in Fig.

.5, applying the brake mechanismto the de- 1 sired extent. As soon as the forward movement of the foot lever and valve casing ceases, the slightest continued movement of i the piston and the valve actuating sleeve will close the valve, l14:0, and shut olf communi- 'cation between the cylinder and the vsuction means, and the piston will hold the brake as applied, as any subsequent movement of the piston forward would open the atmospheric valve, 14, admitting air to the cylinder forward of the iston, and reducing the die# grec of 'rariiication therein, and any reverse movement of the piston would open the suci i tion controlling valve, 140, to-increase the degrec of rarification' forward of the piston.

'To partially release the brakes, the operator releases the pressure on the pedal lever sul- :ciently to permit the spring, 189, to move thevalve casing, 110 rearwardly (to the right) with respect to the valve sleeve, 120, to open the air inlet valve, 141, and admit air to the cylinder forward of the piston, thereby reducing the degree of rarification forward 'of the piston, permitting the draft of the' applied brakes towithdraw the piston suiiiciently to effect the desired release of the engaged friction/surfaces ofv the brake mechanism. i The brakes can -be re-applied by a forward movement of the pedal` lever, 188, and valve casing, 110, sufficiently to close the valve, 141,l and open the suction controllingvalve, 140.

weier y,cause-the'valve casing, v110,'to shift with re- .-spect to the valve actuating sleeve, .120, in a direction opposite to that indicated by the' arrow in Fig. 5, thuslopening the air inlet valve 141, while the suction valve, 140, remains seated, and admitting atmospheric air to the cylinder forward of` the piston. rlhis equalizes pressures on the opposite sides of the piston, and the draft of the applied brakes and the their retracting springs will restore the brakes and piston .to the normal. or off position. 7 v

lt willbe seen that the operator can add his physical force to thewbralre mechanism'in addition t9 that of the actuator, or can operate the brake mechanism by his physical force in case of failure of power, exactly in the same manner as previously described, with reference to Figs. 1 and 2.

' It will be understoodthat the connecting link, 173. from the valve actuating sleeve vto thearm, 174, may be lgiven a provision for lost motion, for example, in the same manner as indicated in Fig. 3, or otherwise, if desired, so that in case of failure of power the brake mechanism may be operated without moving the piston in the manner previously described with reference to Figs. 1, 2 and 3. As will be seen, our improved construction provides a very simple arrangement in which lthe actuator cylinder may be attached to the chassis and directly connected with the usual rock shaft for applying the brake mechanism, while the valve mechanism maybe in- Fserted in the connections between the ordinary foot lever and such rock shaft, and con nected with the actuatorcylinder and with the intake manifold by pipes, portions ofl which are flexible, to provide for the longitudinal movement of the valve casing with rei spect to the parts to which it is connected by such pipesu piston, and released by withdrawing it therefrom, or 'the piston may be'normally submerged in atmospheric air, in which case the brake mechanism is applied by withdrawing air from the cylinder, forward of the piston. The valve mechanism is of the same construche construction,V also provides lost motion between the foot lever and rthe' sov tion in either case, and is so arranged that it said valve mechanism comprising a valve may be used with either type of actuator, by making the proper pipe connections therewith.

It will be understood from the foregoing description that the same valve mechanism herein shown and described is capable of use with various sizes of power actuators and with installations in which the piston of the `actuator is submerged in vacuum, as shown in Figs. 1 and 2, in which the differential valve 40, ,is the air inlet valve, and the equalizing valve, 41, is the suction valve, the extent of opening of which may be determined bythe adjustmentof the rod, 25, and the set nut, 25, where therestricting valve is not used;r and said valve casing is also capable of use with installations in which the piston of the actuator is submerged in atmospheric air,as shown in Figs. 4c and 5, in which case the equalizing valve,-l41, is the air inlet valve, and the different-ialvalve, 140, is the suction valve, the extent of opening of which is limited by the adjustment of the sleeve, 1.21, with respect to the collar, 128. When either of these adjustments is used in an installation to effect the' purpose for which it is intended, the other adjusting means, which will effect the air inlet valve, may be omitted altogether, or so casing exterior to and movable with respect to the actuator'cylinder, and provided with a centrally located' valve chamber and separate chambers co municating therewith and located -on opp site sides of the valve chamber, oppositely disposed valves controlling the communication between the'- valve chamber and said respective chamber, each of saidl separate chambers bezng Aprovided with means for connecting a tubular conmanipulated as to permit any desired open-l ing of the said air inlet valve.

It is to be noted that, in rising the improved valve mechanism herein shown and described, with an actuator in which the piston is submerged either in vacuum or atmospheric air, one of these valves (the valve, 41,Fig. 2,01' 141, Fig. 5), is held partially open when the 'operator operated part is in released or 0H position, so as to effect an equalization of pressures on opposite sides of the piston, and may be termed the equalizing valve, while the other valve, (the valve, 40, in Fig. 2, or 140, in Fig. 5), is opened after the closing ofthe equalizing valve, for the purpose of subjecting the piston to differential pressures on its opposite faces, and may be conveniently termed the differential pressure valve, the same valve being capable of use, as before stated, either with an actuator in which the piston is submerged in Vacuum, when in oif position, as in Fig. 2, or one in which the piston is submerged in atmospheric air, when in oit position, as shown in Fig, 5.

It is obvious that the valve mechanism may be made to control more than one actuator by suitable pipe connections in the casing, indicated, Jfor example, in our former application for Letters Patent of the United States, Serial No. 31, 281, dated May 19,1925.

Vilhat we claim and desire to secure by Letters Patent is r- 1. Controlling vvalve mechanism for power actuators having a cylinder and a single acting piston therein provided with means for connecting it with a part to be operated,

nection therewith, yielding means for normally seating said valves, a valve actuating part extending through the valve casing and valves, -Amovable longitudinally through said valves and having a sealing engagement therewith, and being provided with means for opening one. of said valves by a longitudinal movement of said valve'actuating part in either direction, means for connectingsaid Valve chamber with a tubular connection adapted to be connected to the actuator cylinder, said valve casing and said valve actuating part being provided with means for connecting them in linkage ben tween an operator operated part and the part to be operated by the piston of the'actuator, whereby said valve mechanism may be employed with an actuator cylinder closed at both ends and also with an actuator cylinder communicating at one end with the atmosphere.

2. rControlling valve mechanism for Apower actuators having a 'cylinder and a single acting piston therein provided with means for connecting it with a part to be operated,-

said valve mechanism comprising a valve casing exterior to and movable with respect to the actuatorl cylinder, and provided with a centrally located valve chamber and separate chambers communicating therewith and located on opposite sides of the valve chamber, oppositely disposed valves controlling the' communication between the valve chamber and Said respective chamber, each of said separate chambers being provided with means for `connecting a tubular connection therewith, yielding means for normally seating said valves, a valvesactuating part extending through the valve casing and valves, movable longitudinally throughl said valves and having a sealing engagement therewith, and being providedA with means for opening one of said valves by a longitudinal movement of saidvalve actuating part in either direction, means for connecting said valve chamber with a tubular connection adapted to be connected-to the actuator cylinder, said valve casing and said valve actuating part being provided with means for connecting thenrin linkage-between an operator operated part-'and the part to be operated by the piston of the actuator, and means for normally holding one of said valves in open position to maintain communication between the valve' chamber and one of said separate chambers, whereby said valve mechanism may be employed to control an actuator havinga cylinder closed at both ends, tomaintain the piston submerged in pressures less than atmospheric and to control an actuator having a cylinder open at one end to the atinoksplierc,to maintain the piston normally submerged in air at atmospheric pressure.

3. Valve mechanism dior controlling a power actuator comprising a cylinder and a single acting piston therein, provided with means :tor connecting it tolthe part to bel operated, said valve mechanism .comprising a valvecasing separate from and movable with respect to the cylinder-,and provided with a centrally located chamberand separate chambers on opposite sides thereof communicating therewith, each of saidseparate chambers being provided with means for attaching a tubular connection thereto, a normally closed differential pressure valve controllingV the coi'nmunicationf between the valve chamber and one of said separate chambers, a normally open equalizing valve con olling lthe communication betw en the central chamber and the other of\sai separate chambers, a valve actuating sleeve operatively connected? with4 said valve and movable longitudinally with respect to the valve casing, said valve actuating sleeve beingprovided with means for attaching a tubulan connection adapted to beiconnected with the actuator cylinder,.an operator operated part, said valve casingand valve ac- A 5tuating sleeve being provided with means for connecting them respectively,th e one to said operator operated part andthe other vto the part to be operated by the. actuatorv piston, wherebysfsaid, valve lmechanism may be employed l'to control a power actuator having a cylindergcl'sed at both ends for normally maintaining the piston submerged in pressures less than atmospheric and with an actuator having a cylinder c'ommunicat'- ing with the atmosphere at one end for norlmally maintainingthe piston submerged in yair at atmospheric pressure, and in eithercase inay be made to substantially equalizeY pressures on opposite faces" of the piston at any pointin he pistonl stroke under the control of the operator operated part, to permit the piston ofthe controlled actuator to be retracted.

' 4. Valve mechanism for controlling a lpower actuator comprising a cylinder and a single acting piston therein, provided with means for connecting it to the part to be operated,l said valve mechanism comprising a valve casing separate from and movable with respect to the cylinder, and provided with a acentrally located valve chamber and separate chambers on opposite sidesthereof communieating therewith, each'of said separate chambers being provided with means for attaching atubular connection thereto, a normally closed diiierential pressure valve controlling the communication between the valve cham` ber and one of said separate chambers, a normally open equalizing valve controlling the Vcommunication between the central chamber and the other of said separate chambers, a. valve actuating sleeve operatively connected with said valve and movable longitudinally withrrespect tothe valve casing, said valve vextent of opening of the equalizing valve, andV means for limiting the outward movement'oii' said sleeve with respect to theecasing, to limit thc extent of opening of the differential pressure valve'andvprovide lost motion between the operator operated part and the part to be operated b v the piston, for enabling the operator to apply his physical lforce to the latter'.

5. Valve mechanism for controlling a power actuatoricomprising a cylinder and a single acting piston therein, provided 'with means for connecting it to the part to be operated, said valve mechanism comprising a valve casing separate from and movable with respect tothe cylinder, and provided with a vcentrally located valve chamber and separate .chambers on opposite sides/thereof communibers being provided with means for attaching a tubular. connection thereto, a normally closedgdiierential pressure valve controlling the communication between the valve chamberand one of said separate chambers, a normally open equalizing valve controlling the communication between the central chamber and the other of said separate chambers, a valve actuating sleeve operatively connected with said valve and, movable longitudinally with respect to the valve casing, said valve actuating sleeve beingoprovidedwith means for attaching a tubular connection adapted to be connected with the actuator cylinder, an operator operated part operatively connected with the valve casing, said valve actuating sleeve being provided with means for connecting it with the part to be operated by the actuator piston, a stop on the valve actuating sleeve, an adjustable stop sleeve adjustably connected with the valve casing and surrounding said valve actuating sleeve for engaging said stop,'to provide limited lost mtion between the operator operated part and the part to be'o'prated by the actuator piston,

and to limit the eixtent of opening of the differential pressure valve.

6. Valve mechanism for controlling a power actuator having a cylinder communicating with the atmosphere at one end, and a single acting piston provided with means for connecting it with a part to be operated, said valve mechanism comprising a valve casing provided with a central chamber and separate chambers on opposite sides thereof and communicating therewith, one of said separate chambers being provided with means for connecting it with a source of suction and 'the other being provided with means for connecting it with the atmosphere, oppositely disposed valves for controlling the communication between said central chamber and said respective separate chambers, means for connecting said central chamber with the actuator cylinder between the closed end thereof and the piston, a valve actuating part movable longitudinally with respect to the valve casing, operatively connected with said valves for opening one by a movement in either direction, yielding means for normally seating said valve, an operator operated part, said valve casing and said valve actuating part being connected respectively, the one with the operator operated part and the other with the part to be operated by the actuator piston.

7. Valve mechanism for controlling a power actuator having a cylinder communieating with the atmosphere at one end, and a single acting piston provided with means for connectinghit with a part to be operated, said valve mec anism comprising a valve casing provided with a central chamber and separate chambers on opposite sides thereof and communicating therewith, one of said separate chambers being provided with means for connecting it with a source of suction and the other being provided with means for connecting it with the atmosphere, oppositely disposed valves for'controlling the communication between said central chamber and said respective separate chambers, means for connecting said central chamber with the actuator cylinder between the closed end thereof and the piston, a valve' actuating part movable longitudinally with respect to the valve casing, operatively connected with said valves for opening one by a movement in either direction, yielding means for normally seating said valve, an operator operated part, said valve casing and said valve actuating part being connected respectively, the one with the operator operated part and the other with the part to be operated by the actuator piston, and means for normally holding in open position the valve controlling the communication between the central chamber of the valve casing and the separate chamber communicating with the atmosphere, to normally maintain the piston of the actuator submerged in air at atmospheric pressure, and to substantially7 equalize pressures on opposite faces of the piston of the actuator at an point of its stroke, to permit the piston to be retracted.

8. Valve mechanism for controlling a power actuator having a cylinder communi eating with the atmosphere at one end, and a single acting piston provided with ,'means for connecting it with a part to be operated, said valve mechanism comprising a valve casing provided with a central chamber and separate chambers on opposite sides thereof and communicating therewith, one of said separate chambers being provided with means for connecting it with a source of suction and the other being provided with means for connecting it with the atmosphere, oppositely disposed valves for controlling the communication between said central chamber and said respective separate chambers, means for connecting said central chamber with the actuator cylinder between the closed end thereof and the piston, a valvev actuating part movable longitudinally with respect to the valve casing, operatively connected with said valves for opening one by a movement in either direction, yielding means for normally seating said valve, an operator operated part, said valve casing and said valve actuating part being connected respectively, the one with the operator operated part and the other with the part to be operated by the actuator piston, and means for normally holding in open position the valve controlling the communication between the central chamber of the valve casing and the separate chamber communieating with the atmosphere, to normally maintain the piston of the actuator submerged in air at atmospheric pressure, and to substantially equalize pressures on opposite faces of the piston of the actuator at any point of its stroke, to permit the piston to be retracted, and co-acting stops on the valve actuating part and the valve casing, for limiting the extent of opening of the valveinterposed between said central chamber and the end chamber communicating with the suctionv means, and for enabling the operator to apply his physical force to the part to be operated by the actuator piston.

In testimony whereof we aix our signatures. i

" CALEB SMITH BRAGG.

VICTOR W. KLIESRATH. y 

